1. Field of the Invention
The present invention relates to an endoscopic high-frequency knife which is typically inserted trans-endoscopically into a body to dissect or resect mucosae of body tissues, and the like, via a passage of electric current through the knife.
2. Description of the Related Art
A typical endoscopic high-frequency knife is constructed and arranged so that a high-frequency cutting electrode is attached to a tip of an insulating flexible sheath which is inserted into a treatment tool insertion channel of an endoscope. In such an endoscopic high-frequency knife, it is difficult to determine the cutting depth because the cutting tip of the high-frequency cutting electrode sinks into the cut during an endoscopic surgical operation for dissecting a submucosa and the like. Therefore, there is a possibility of a body tissue being accidentally dissected excessively by an unintentional depth.
To prevent this problem from occurring, an endoscopic high-frequency knife in which the high-frequency cutting electrode is formed in a rod which is bent in a manner such that the tip of the rod is exposed from the surface of a mucosa, during the aforementioned endoscopic surgical operation for dissecting a submucosa, so that one can perform this endoscopic surgical operation while viewing the tip of the high-frequency cutting electrode on a monitoring screen has been proposed in Japanese Patent Publication No. 2002-153485.
However, even if the tip of the high-frequency cutting electrode, which is exposed from the surface of a mucosa during the endoscopic surgical operation for dissecting a submucosa, can be viewed on a monitoring screen with the an endoscopic high-frequency knife such as disclosed in the aforementioned Japanese Patent Publication, dissected surfaces of the submucosa which are in the process of being dissected by the high-frequency cutting electrode cannot be viewed in real time. Accordingly, it is not always the case that a medically-optimum prescribed range of submucosa can be dissected with such a conventional endoscopic high-frequency knife.
In a surgical operation for dissecting an affected area with a conventional endoscopic high-frequency knife, firstly the distal end of the endoscope is introduced into the body to a position suitable for surgical treatment for the affected area, subsequently the endoscopic high-frequency knife is projected from the tip of the insertion portion of the endoscope to precisely face the affected area, and finally the affected area needs to be dissected by a combination of a steering operation of the endoscope and a steering operation of an appropriate treatment tool. This procedure is very complicated.